Just reiterating what the other gals have said...

Get slicks or semi-slicks when you ride on the road... start in a low gear...

Take it easy for the first little while... before a race I make sure I have about 30 mins to warm up and ride slowly (between 22 - 27kph) just to get the legs remembering that I am on a bike and thinking about what I am going to ask of them.

On a training ride or recovery ride, I expect my legs to feel muddy for 20-30 minutes and then all of a sudden every thing feels much easier.

And sitting in behind someone once you have warmed up is a great way to train, particulalrly if they go just a fraction faster than you usually do...